I always thought those motions were very easy. At most for some games I had issues with doing double qcb, but I learned that the problem was that I didn't put enough emphasis on the second forward. The only ones I have issue doing consistently are formerly the charge supers(Which I now how to do consistently), sometimes double full circle motion, and most of the time complicated and confusing motions that mostly come from Fatal Fury games.(Such as Geese's pretzel motion, just ones that are very specific and much longer than usual.) Though even those complicated ones depend on the game, for an example, I am able to do Vega's flying barcelona special in Street Fighter 4, yet I have trouble doing it consistently in CvS2. Other moves like the previously mentioned pretzel also vary consistency game to game despite it being the exact same motion.
Then again, most friends and people that I know have trouble doing a basic hadoken motion. One of my friends that I just had over this weekend, for an example, can sometimes do that motion if he does it over and over, then he might get one or two out of it. But he can't do it consistently at all. Then again he often pulls off weird stuff that I question whenever he just randomly goes at it, throwing around random commands and button combinations. Whether it be combos or raging demons.